Concomitant occurrence of multicentric hemangiosarcoma and histiocytic sarcoma in a dog

Histiocytic sarcoma (HS) is uncommon malignant neoplasia of round cells with marked predilection in Rottweiler and Bernese Mountain. The disseminated form, which mainly affects the spleen, lungs, lymph nodes, bone marrow, skin, and subcutis, presents a quick and aggressive clinical behavior. Hemangiosarcoma (HAS) is a malignant neoplasm of endothelial vessel cells commonly reported to affect the right atrium of dogs' hearts. A male Rottweiler, five years old, presented flaccid paraplegia and progressive muscular atrophy in the temporal, masseter, and limbs muscles; Due to the clinical stage of the animal, euthanasia was conducted. During the necroscopic examination, it was noticed that several masses presented different sizes; some were whitish, and others were reddish and spread in multiple organs (lungs, heart, spleen, stomach, kidneys, brain, medulla, skeletal muscle, and pre-scapular lymph node). Microscopically, in some organs such as the stomach, right ventricle, lungs, and medulla, it was noticed a proliferation of myeloid cells, highly cellular, with poor demarcation, no encapsulation, and with the infiltrative growth pattern of cells with high pleomorphism. Numerous tumoral emboli were observed in the spleen, brain, skeletal muscle, and lymph node. These cells were submitted for immunohistochemistry and were positive for CD18 (HS antibody). In the right atrium, liver, and kidney it was observed malignant and infiltrative endothelial proliferation (HSA) and emboli in the medulla. Therefore, we conclude that both neoplasms (HS and HSA) cause the animal's paraplegia due to their embolism and metastasis to the spinal cord and skeletal muscle.(AU)

Metastatic calcification and granulomatous grastroenteritis associated to Pythium insidiosum in a dog

Pythiosis is a granulomatous process of which the oomycete Pythium insidiosum is its etiological agent. It can affect animals and humans alike and its infection occurs when free zoospores in the water get in contact with the target tissues and encyst. The disease often occurs in tropical places with abundance of water and aquatic plants that host the fungus. Dogs infection is predominantly gastric with granuloma formations in the stomach and intestine with progressive signs of vomiting, weight loss and diarrhea. In this case report, we described clinical, surgical, necroscopic and histopathological findings of a one year and two months old, male boxer that presented clinical signs of anorexia and persistent vomiting. It was noticed on ultrasound examination an increase in stomach and intestine thickness. Laparotomy confirmed a mass affecting the gastric wall which, an incision biopsy, showed an abundant fibrous tissue associated with granulomatous reaction that was surrounded by tubuliform structures. Due to clinical complications, euthanasia was performed and in necroscopic examination a markedly increased stomach and duodenum was observed. An; histological examination of this areas it was observed that they contained granulation tissue with giant cells and epithelioids macrophages around necrosed areas associated with lymphocytes infiltrate. Also, it was possible to observe tubuliform structures by the Grocott-Gomori’s Methenamine Silver (GMS) stain, this finding is compatible with the agent Pythium insidiosum. Therefore, this presumptive identification was confirmed by PCR analysis which amplicon had 97.83% similarity with current available genomic sequence of P. insidiosum.

Metastatic calcification and granulomatous grastroenteritis associated to Pythium insidiosum in a dog

Pythiosis is a granulomatous process of which the oomycete Pythium insidiosum is its etiological agent. It can affect animals and humans alike and its infection occurs when free zoospores in the water get in contact with the target tissues and encyst. The disease often occurs in tropical places with abundance of water and aquatic plants that host the fungus. Dogs infection is predominantly gastric with granuloma formations in the stomach and intestine with progressive signs of vomiting, weight loss and diarrhea. In this case report, we described clinical, surgical, necroscopic and histopathological findings of a one year and two months old, male boxer that presented clinical signs of anorexia and persistent vomiting. It was noticed on ultrasound examination an increase in stomach and intestine thickness. Laparotomy confirmed a mass affecting the gastric wall which, an incision biopsy, showed an abundant fibrous tissue associated with granulomatous reaction that was surrounded by tubuliform structures. Due to clinical complications, euthanasia was performed and in necroscopic examination a markedly increased stomach and duodenum was observed. An; histological examination of this areas it was observed that they contained granulation tissue with giant cells and epithelioids macrophages around necrosed areas associated with lymphocytes infiltrate. Also, it was possible to observe tubuliform structures by the Grocott-Gomoris Methenamine Silver (GMS) stain, this finding is compatible with the agent Pythium insidiosum. Therefore, this presumptive identification was confirmed by PCR analysis which amplicon had 97.83% similarity with current available genomic sequence of P. insidiosum.(AU)